4 ms·

And the list goes on! But from an engineering point of view, I just don't find ICEs elegant. Too many moving pieces, and all that for about 30% efficiency (the

And the list goes on! But from an engineering point of view, I just don't find ICEs elegant. Too many moving pieces, and all that for about 30% efficiency (the remaining 70% is lost as waste heat). Good thing gasoline is so energy-dense, because when you're wasting 70% of your energy, you need that.

bkanber 14y ago
30% is roughly the peak efficiency of an ICE. Average efficiency throughout a driving cycle is more like 17%.
Arelius 14y ago
It turns out, however that when you're talking about transportation, energy density is much more important than efficiency generally speaking.
sliverstorm 14y ago
ICEs are, at their core, plenty elegant. The trouble is efficiency and low emissions are not their strong points. I would argue that efficiency and low emissions do not preclude something from being elegant. Steam plants can also be elegant, and they can be extremely efficient and low-emissions, but a steam plant cannot be bolted onto a motor car or a small aeroplane for which a turbine would be inappropriate. All forms of heat engines have their upsides and downsides. Anyway, at the end of the day, consumers don't care one iota about engineering elegance.
- dredmorbius 14y ago
  The biggest ongoing problem is going to be CO2 emissions. Given few alternatives to ICEs (EVs and hybrid vehicles are available, but unsubsidized TCO remains higher, and even accounting for carbon costs may be higher, I'd have to research that), we're going to have liquid-fueled vehicles for a long time. The real question is where that fuel will be sourced.
  - sliverstorm 14y ago
    CO2 emissions is coupled to gasoline, not ICEs. Hydrogen ICEs do not give off CO2.
    - danielweber 14y ago
      The emissions are going to come from wherever the energy is made. I'd like to see efforts at using energy sources to manufacture gasoline from environmental sources of carbon, making the fuel carbon-neutral. How does that compare to electric vehicles?
      - sliverstorm 14y ago
        Ok, fine, if you burn coal to produce hydrogen, yes. Hydrogen fuel then indirectly produces CO2. There have been efforts to do this; basically any form of biodiesel that is produced by bacteria can probably be considered carbon-neutral.
        fleitz 14y ago
        No kidding, I wonder where the poster thinks power on the east coast comes from.
    - dredmorbius 14y ago
      CO2 emissions is coupled to fossil fuels, not necessarily gasoline, if you're talking about renewably-generated gasoline (say from biofuels, though I suspect biodiesel is more likely). And if you're getting hydrogen (an energy storage medium, not an energy source, and an awfully low-density one to boot on a volumetric basis, with significant storage and transport issues) from fossil-fuel generated electricity, you've mostly just transported the CO2 emissions problem (modulo carbon sequestering, which is presently and likely forever highly uneconomic). I address issues of alternate fuels in a prior post, and suspect we'll see liquid hydrocarbons, of some stripe, for quite some time. http://news.ycombinator.com/item?id=5204104 http://news.ycombinator.com/item?id=5204104 Edit: speling
dredmorbius 14y ago
But for all of that, liquid hydrocarbons offer among the best weight/volume energy storage capacity available to us. The alternatives: EVs, LNG, hydrogen, compressed air, flywheels, etc., just don't hack it. For an efficiency perspective, the next best bet is human-powered vehicles, but these aren't an option for all people. Transit and dense infrastructures are your next best bet. While I see us moving from fossil fuel, I still see liquid fuels playing an important role in mechanized transit (ground, water, air) for as long as we're technologically capable of doing so.
teeja 14y ago
I share your dislike of ICEs but you are being far too kind with that 30%. At best 20% is (high-end) typical. Which means that for every 5 gallons of fuel you feed it, it throws away 4. That is SUCH poor engineering that it's verging on insane that we've embraced these stinking, finicky beasts long enough to destroy most of the planet's (easy) fossil fuel reserves.
thrownaway2424 14y ago
It sounded like the guy from the Times would have welcomed as much "waste heat" as he could get his hands on.

bkanber 14y ago

30% is roughly the peak efficiency of an ICE. Average efficiency throughout a driving cycle is more like 17%.

Arelius 14y ago

It turns out, however that when you're talking about transportation, energy density is much more important than efficiency generally speaking.

sliverstorm 14y ago

ICEs are, at their core, plenty elegant. The trouble is efficiency and low emissions are not their strong points. I would argue that efficiency and low emissions do not preclude something from being elegant. Steam plants can also be elegant, and they can be extremely efficient and low-emissions, but a steam plant cannot be bolted onto a motor car or a small aeroplane for which a turbine would be inappropriate. All forms of heat engines have their upsides and downsides. Anyway, at the end of the day, consumers don't care one iota about engineering elegance.

dredmorbius 14y ago
The biggest ongoing problem is going to be CO2 emissions. Given few alternatives to ICEs (EVs and hybrid vehicles are available, but unsubsidized TCO remains higher, and even accounting for carbon costs may be higher, I'd have to research that), we're going to have liquid-fueled vehicles for a long time. The real question is where that fuel will be sourced.
- sliverstorm 14y ago
  CO2 emissions is coupled to gasoline, not ICEs. Hydrogen ICEs do not give off CO2.
  - danielweber 14y ago
    The emissions are going to come from wherever the energy is made. I'd like to see efforts at using energy sources to manufacture gasoline from environmental sources of carbon, making the fuel carbon-neutral. How does that compare to electric vehicles?
    - sliverstorm 14y ago
      Ok, fine, if you burn coal to produce hydrogen, yes. Hydrogen fuel then indirectly produces CO2. There have been efforts to do this; basically any form of biodiesel that is produced by bacteria can probably be considered carbon-neutral.
      - fleitz 14y ago
        No kidding, I wonder where the poster thinks power on the east coast comes from.
  - dredmorbius 14y ago
    CO2 emissions is coupled to fossil fuels, not necessarily gasoline, if you're talking about renewably-generated gasoline (say from biofuels, though I suspect biodiesel is more likely). And if you're getting hydrogen (an energy storage medium, not an energy source, and an awfully low-density one to boot on a volumetric basis, with significant storage and transport issues) from fossil-fuel generated electricity, you've mostly just transported the CO2 emissions problem (modulo carbon sequestering, which is presently and likely forever highly uneconomic). I address issues of alternate fuels in a prior post, and suspect we'll see liquid hydrocarbons, of some stripe, for quite some time. http://news.ycombinator.com/item?id=5204104 http://news.ycombinator.com/item?id=5204104 Edit: speling

dredmorbius 14y ago

But for all of that, liquid hydrocarbons offer among the best weight/volume energy storage capacity available to us. The alternatives: EVs, LNG, hydrogen, compressed air, flywheels, etc., just don't hack it. For an efficiency perspective, the next best bet is human-powered vehicles, but these aren't an option for all people. Transit and dense infrastructures are your next best bet. While I see us moving from fossil fuel, I still see liquid fuels playing an important role in mechanized transit (ground, water, air) for as long as we're technologically capable of doing so.

teeja 14y ago

I share your dislike of ICEs but you are being far too kind with that 30%. At best 20% is (high-end) typical. Which means that for every 5 gallons of fuel you feed it, it throws away 4. That is SUCH poor engineering that it's verging on insane that we've embraced these stinking, finicky beasts long enough to destroy most of the planet's (easy) fossil fuel reserves.

thrownaway2424 14y ago

It sounded like the guy from the Times would have welcomed as much "waste heat" as he could get his hands on.